THE SENSITIVITY OF THE MICRONUCLEUS ASSAY FOR THE DETECTION OF OCCUPATIONAL EXPOSURE TO VINYL-CHLORIDE MONOMER

The micronucleus assay was performed in the peripheral lymphocytes of 32 subjects occupationally exposed to vinyl chloride monomer (VCM) div ided into two groups according to years of employment. Blood samples w ere taken in the period from 24 h to 90 days following a transitory ex posure to elevated VCM concentrations of 300 ppm due to the technologi cal process. In subjects with a longer period of employment micronucle us frequencies decreased in proportion to the length of the interval a fter the last exposure to VCM. The results confirm that the micronucle us assay can serve as a suitable indicator of the time elapsed after l ast exposure to elevated concentrations of environmental mutagen. It c an be assumed that duration of employment may contribute to the occurr ence of the cumulative effect produced by exposure to elevated VCM con centrations.